Species of cDNA corresponding to choline acetyltransferase and protein 41C5 were cloned; the expression of genes for both species of protein are regulated in neurons during development. In addition, cloned cDNA recombinants were obtained for species of mRNA that are positively or negatively regulated by cyclic CMP in neuroblastoma or hybrid cells. A monospecific antibody directed against Alpha-transducin was used to determine the distribution of Alpha-transducin in chicken retina. Alpha-Transducin was found to be abundant in rod photoreceptors, but was not detected in cones. These results suggest that rods and cones either express different species of Alpha-transducin or have different mechanisms of phototransdution. The addition of bradykinin to NG108-15 cells results in hyperpolarization followed by a prolonged depolarization. Concomittantly, cellular levels of inositol-1,4,5-trisphosphate increase and secretion of acetylcholine from cells increases. Injection of inositol-1,4,5-trisphosphate or Ca2+ ions into the cytoplasm of cells results in cell hyperpolarization followed by depolarization, similar to the effects elicited by extracellular bradykinin. The effects of bradykinin on cell membrane potential are inhibited by pertussis toxin. Bradykinin stimulates low Km GTPase activity in NG108-15 membrane preparations, but not in membranes prepared from cells treated with pertussis toxin. Incubation of NG108-15 membranes from cells that had been treated with pertussis toxin with a mixture of purified No and Ni restores bradykinin-dependent GTPase activity. These results show that [bradykinin-receptor] complexes interact with No or Ni and suggest that No or Ni may couple bradykinin receptor activation with the activation of phospholipase C and the inhibition of adenylate cyclase.